Processing method of black tea

Abstract

The invention relates to the technical field of tea processing, in particular to a black tea processing method for improving color, aroma and taste quality of black tea. Comprising the following steps: S1, withering; s2, vibration: placing the withered leaves in a vibration groove for transmission and vibration to obtain spread-cooled leaves; s3, performing rolling; s4, performing fermentation; s5, primary drying; s6, fermentation: putting the tea leaves subjected to primary drying in the step S5 into a fermentation room for fermentation to obtain fermented leaves; and S7, sufficient drying. On the basis of the existing processes of withering, rolling, fermentation, primary drying, re-drying and the like for black tea production, on one hand, a launder vibration process is introduced, conversion of aroma precursor substances is accelerated, and meanwhile excessive mechanical damage to leaves in the traditional rocking process is relieved. On the other hand, according to the method, polyester catechin, theaflavin and thearubigins are synthesized by adopting a fermentation process after the black tea is initially dried, so that the taste and the liquor color quality of the black tea are further improved.

Description

Technical Field

[0001] The invention relates to the technical field of tea processing, in particular to a black tea processing method for improving the color, aroma and flavor quality of black tea. Background Art

[0002] Most black tea is processed from summer or autumn tea leaves. Due to the high content of tea polyphenols and low content of amino acids in summer and autumn tea leaves, and the limitations of traditional black tea processing technology, the processed black tea generally has quality defects such as strong bitterness, green, turbid soup color, and no distinctive aroma, which seriously affects the market expansion of tea. Innovating traditional black tea processing technology and improving the color, taste and aroma quality of black tea are the keys to the development of black tea. At present, the main measures to improve the color, aroma and quality of black tea are:

[0003] (1) Improve the traditional black tea processing technology. Improving the traditional black tea processing technology involves optimizing key steps such as withering, rolling, fermentation, and drying. Zhang Xianglin et al. showed that the use of hot air withering technology can significantly increase the content of volatile compounds and catechins in black tea. Wu Zhuanrong et al. effectively reduced the green smell of tea leaves and enhanced the sweet and floral aroma by extending the sunlight withering time. Zhu Hongkai et al. used low-temperature rolling (20℃±2℃) to increase the amino acid content, reduce the loss of tea polyphenols and caffeine, increase the content of theaflavins, and enhance the freshness and aroma quality of the tea soup. During the fermentation process, time, temperature, humidity, and oxygen flow are key quality factors. Xie Nianci et al. found that fermenting Baojing Golden Tea No. 1 at 28℃ for 2 hours and then reducing the temperature to 22℃ for another hour can significantly enhance the floral aroma of black tea. Pan Ke et al. pointed out that oxygen fermentation can enhance the aroma, taste, soup color, and brightness of the bottom of the leaves of black tea more than natural fermentation.

[0004] (2) Introducing processing technologies of other teas. Making green tea is the core process of oolong tea processing, which includes alternating processes such as sun drying, shaking and static spreading. Its essence is to damage the edges of the leaves by physical means, thereby promoting the transformation of chemical substances inside the tea leaves, especially the oxidation of phenolic compounds, which helps the formation and transformation of aroma components. For example, Liu Shujuan et al. applied the making green process of oolong tea to the processing of black tea and found that this method can effectively improve the aroma quality of black tea.

[0005] Prior art CN 112741167 A discloses a method for processing large-leaf fruity black tea, comprising the following steps: S1, fresh leaves: picking fresh leaves with one bud and one leaf or one bud and two leaves from Yunnan large-leaf tea trees; S2, sunlight withering; S3, natural withering and shaking indoors; S4, rolling; S5, fermentation; and S6, drying. The invention provides a method for processing large-leaf fruity black tea, which adds the shaking process of oolong tea to the traditional black tea processing process. Through multiple shaking processes, the tea leaves are continuously subjected to vibration, friction and collision, thereby accelerating the enzymatic oxidation induced. Its oxidation products and other conversion products of contained substances are continuously accumulated during the greening process, emitting a unique floral and fruity aroma, forming a fruity black tea that adds a refreshing floral and fruity aroma to the sweet and fragrant traditional Kung Fu black tea, which is conducive to improving the single problem of tea products and improving the ability to respond to the market.

[0006] Prior art CN 106343051A relates to a method for making black tea. It includes five steps: withering, shaking, rolling, and airing, of which the airing is divided into three stages. The content of tea polyphenols and caffeine in the black tea produced by the invention is greatly reduced compared with that in traditional black tea, the oxidation polymerization of tea polyphenols is more complete, the production of theaflavins, thearubigins, etc. is increased, the pharmacological and health functions of black tea are enhanced, and the harm of caffeine to the human body is reduced; the invention does not add high temperature during the production of black tea, and it can be stored for a long time, and the ingredients in the black tea will not change: the invention adds a shaking process to the production of black tea, which fully enhances the aroma of tea leaves, and the aroma is fresh and mellow, like floral and fruity aroma.

[0007] However, the above three prior art tea-making processes have obvious defects, especially the continuous shaking of tea leaves, which can easily lead to excessive mechanical damage to the tea leaves, leading to uneven fermentation and affecting the color of the tea leaves. During the multiple shaking of tea leaves, the tea leaves are prone to excessive hydrolysis and redox reactions, leading to the loss of key aroma components such as linalool, methyl salicylate, and α-ionone, which directly affects the quality of the finished tea. In addition, repeated mechanical action not only increases the labor intensity, but also makes the production process difficult to automate and scale.

[0008] In addition, studies have shown that after the initial drying of the raw tea, the polyphenol oxidase and peroxidase in the black tea are not completely inactivated, and their activities are reduced to about 8% and 7.5% respectively when withering. At the same time, tea polyphenols, catechins and other internal components also have a certain amount of residue, which has a biochemical basis for further fermentation and transformation. Xia Yimin and others borrowed the "pile fermentation" process of black tea and carried out post-fermentation treatment on the finished raw tea. They found that this method can significantly reduce the ratio of ester catechins to simple catechins, reduce bitter taste, and increase the content of quality components such as theaflavins and thearubigins. In addition, Zhou Qinyu and others found that the 3-hour pile treatment after the initial drying of the raw tea significantly increased the content of theaflavins, fruity alcohols and ketone aroma substances in the black tea, and improved the soup color, taste and aroma quality of the black tea.

[0009] Although previous measures have improved the intrinsic quality of black tea to a certain extent, they have not yet fundamentally solved the problems faced by black tea, such as strong bitterness, lack of aroma, low intrinsic quality, and difficulty in expanding the consumer market. Summary of the invention

[0010] The present invention provides a new black tea processing method, which enables the black tea to form excellent quality characteristics of bright orange-red soup color, rich floral and fruity aroma, and mellow and fresh taste during processing, breaking through the difficult problems of quality defects of color, aroma and taste of traditional black tea, and effectively alleviating the industrial problem of waste of fresh tea leaf resources in summer and autumn.

[0011] In order to achieve the above object, the present invention adopts the following technical solution:

[0012] A method for processing black tea comprises the following steps:

[0013] S1. Withering: placing fresh tea leaves in a withering tank for withering to obtain withered leaves;

[0014] S2, vibration: placing the withered leaves in a vibration tank to transmit vibration to obtain cooling leaves;

[0015] S3, rolling and twisting: rolling and twisting the spread-out leaves to de-block them, thereby obtaining de-blocked leaves;

[0016] S4, fermentation: putting the deblocked leaves into a fermentation room at a temperature of 25°C-28°C and a humidity of 90%-95% for fermentation until more than 85% of the leaves are red and yellow;

[0017] S5, primary drying: drying the tea leaves fermented in step S4 at 115-125°C, and then letting them stand to cool;

[0018] S6, fermentation: placing the tea leaves that have been initially dried in step S5 in a fermentation room for fermentation to obtain fermented leaves;

[0019] S7. Fully dry: dry the fermented leaves at 85-95℃ until the moisture content is less than 7%.

[0020] In a preferred embodiment, the fresh tea leaves are fresh leaves from summer or autumn.

[0021] In a preferred embodiment, the fresh tea leaves are one bud and two leaves of the oak leaf type.

[0022] In a preferred embodiment, the leaf surface of the withered leaves in step S1 loses its luster, the leaf color turns dark green, the leaf texture is soft and has a slight fragrance.

[0023] In a preferred embodiment, the withering temperature in step S1 is 25-27° C. and the humidity is 60%-70%.

[0024] In a preferred embodiment, the withering in step S1 is first withering in a ventilated environment for 30-60 minutes, and then withering naturally for 8-9 hours to obtain withered leaves.

[0025] In a preferred embodiment, the vibration tank in step S2 is a ZDC-40 vibration tank.

[0026] In a preferred embodiment, the transmission vibration process in step S2 is as follows: the vibration power is 0.50-0.60 kW, the transmission speed is 0.080-0.090 m / s, the transmission vibration is allowed to stand for 65-75 seconds, and this is repeated several times.

[0027] Transmission vibration is achieved by controlling the acceleration of forward vibration to be different from that of backward vibration, so that the material on it moves forward more in the feeding direction and moves backward less in the opposite direction, thereby realizing material transportation.

[0028] The power of vibration determines the amplitude of the fresh leaves' vibration inside. If the power is too high, the edges of the fresh leaves will be severely damaged, which is not conducive to preserving the integrity of the leaves of the finished tea. If the power is too low, the effect of accelerating the conversion of aroma precursors will not be achieved.

[0029] If the transmission time is too long or the transmission speed is too slow, the leaf edges will be over-fermented, and the color (darker), aroma (loss of floral and fruity aroma), and taste (more astringent) of the black tea will be affected; if the time is too short or the transmission speed is too fast, the conversion of aroma precursors will not be accelerated.

[0030] In a preferred embodiment, the transmission vibration process in step S2 is as follows: the vibration power is 0.50-0.60 kW, the transmission speed is 0.080-0.090 m / s, the transmission vibration is allowed to stand after 65-75 seconds, and it is repeated 3-6 times.

[0031] In a preferred embodiment, the transmission vibration in step S2 is repeated 4 times.

[0032] In a preferred embodiment, the transmission vibration in step S2 is repeated 5 times.

[0033] Too many times, that is, the transmission vibration time is too long, will first cause excessive damage to the leaf edges, which is not conducive to retaining the integrity of the leaves. The leaves of the finished tea will lose too much water, which is not conducive to the subsequent fermentation step. The color (darker), aroma (loss of floral and fruity aroma) and taste (more astringent) of the black tea will all be affected.

[0034] In a preferred embodiment, the rest time after the latter transmission vibration in step S2 is longer than the rest time after the former transmission vibration.

[0035] In a preferred embodiment, the transmission vibration process in step S2 is: let stand for 3-7 minutes after the first transmission vibration, let stand for 8-12 minutes after the second transmission vibration, and let stand for 13-18 minutes after the third transmission vibration.

[0036] The standing time is gradually lengthened because the leaves lose water at the edges during the previous vibration process. The water in the leaf stalks is transferred to the inside of the leaves during the standing time. As the number of vibrations increases, the degree of water loss at the leaf edges becomes more and more serious. The standing time is increased accordingly, which is conducive to the full transfer of water in the leaf stalks to the inside of the leaves.

[0037] In a preferred embodiment, the kneading process in step S3 is: first kneading for 40-60 minutes at a certain frequency in a kneading machine, and then kneading in the air for 3-5 minutes; the kneading speed is 40-55r / min.

[0038] In a preferred embodiment, in step S3, kneading is first performed at a certain frequency until the cell damage rate reaches more than 85% and the strip forming rate reaches more than 70%; and then air kneading is performed for 3-4 minutes.

[0039] In a preferred embodiment, in step S4, the fermented tea leaves are piled up to a thickness of 3.5-4.5 cm.

[0040] In a preferred embodiment, the fermentation time in step S4 is 1.5-2h.

[0041] In a preferred embodiment, the tea leaves fermented in step S5 are dried at 115-125° C. for 10-15 seconds.

[0042] In a preferred embodiment, the fermentation temperature in step S6 is 27-30° C. and the humidity is 65%-70%.

[0043] In a preferred embodiment, the fermentation time in step S6 is 3.5-4h.

[0044] In a preferred embodiment, the fermented tea leaves in step S6 are stacked to a thickness of 5-6 cm.

[0045] In a preferred embodiment, when the tea leaves are fully dried in step S7, the thickness of the tea leaves is 1-2 cm.

[0046] In a preferred embodiment, the drying time in step S7 is 50-80 minutes.

[0047] The present invention aims at the quality defects of black tea processed by traditional technology, such as strong bitter taste, greenish color, turbid soup color, insufficient aroma, and the resulting bottleneck problems in industry development, such as limited expansion of the black tea market, serious abandonment of fresh tea leaves in summer and autumn, and low utilization rate. The present invention innovatively introduces flow channel vibration and fermentation conversion processes at specific time points to provide a processing method for improving the color, aroma and flavor quality of black tea.

[0048] The present invention is based on the existing black tea production withering, rolling, fermentation, primary drying, re-drying and other processes. On the one hand, the flow trough vibration process is introduced, and the frequency and amplitude of the flow trough vibration are accurately adjusted to achieve uniform and gentle vibration of the fresh tea leaves, accelerate the conversion of aroma precursor substances, stimulate geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenylethanol and other floral and fruity aroma substances, and reduce the excessive mechanical damage of the leaves caused by the traditional shaking process. On the other hand, the method adopts an fermentation conversion process after the black tea is initially dried, and the black tea after the initial drying is piled in an oxygen-permeable environment, and the activity of the polyphenol oxidase that is not completely passivated is used to continue enzymatic fermentation to synthesize polyester catechins, theaflavins and thearubigins, and further improve the taste and soup color quality of the black tea. Through the processes of withering, flow trough vibration, rolling, fermentation, primary drying, fermentation conversion, and full drying, the present invention improves the color, aroma and taste quality of the black tea, and the obtained black tea has a bright orange-red color, a strong floral and fruity aroma, and a strong and fresh taste.

[0049] Compared with the prior art, the advantages of the present invention are:

[0050] 1. The present invention innovatively introduces a flow channel vibration process before rolling. Compared with the traditional tea-making process, this process has the following advantages: (1) Accurately adjust the vibration frequency and amplitude to achieve uniform and gentle vibration, reducing excessive damage to the leaves. (2) Low-frequency vibration accelerates the collision between the enzyme and the substrate, promotes the dynamic change of the enzyme conformation, and improves the catalytic efficiency. (3) Compared with the tea-making method of violent friction, the flow channel vibration generates a trace amount of local heat, avoids overheating problems, and maintains a temperature suitable for enzyme activity. (4) The flow channel vibration evenly distributes the tea leaves, increases the oxygen contact area and gas exchange efficiency, and accelerates the redox reaction. This process stimulates precursor substances that are conducive to the production of floral and fruity aromas, while maintaining the integrity of the leaves, improving processing efficiency and quality consistency. The flow channel vibration process introduced before rolling will cause the water to be lost faster, increase the rolling rate, reduce the rolling time, improve the uniformity of fermentation, and shorten the fermentation time.

[0051] 2. Based on the traditional black tea processing technology, the present invention innovatively introduces the fermentation conversion process before the full drying step, making full use of the polyphenol oxidase activity that is not completely inactivated in the tea leaves after rough fire drying, and promoting the further conversion of the tea leaves under the heat and humidity conditions generated by the tea leaves themselves, which not only increases the content of key flavor substances such as water extract, tea polyphenols, amino acids, caffeine and soluble sugar in the tea leaves, but also reduces the ratio of ester catechins to total catechins, reducing the bitter taste of black tea. In addition, the fermentation conversion process improves the formation of key quality components such as polyester catechins and theaflavins in black tea, and improves the color quality of tea soup.

[0052] 3. Aiming at the limitations of the current black tea processing technology, this method introduces two innovative processes, namely, launder vibration and fermentation. The produced black tea has a bright orange-red color, rich floral and fruity aroma, and a mellow and refreshing taste, which comprehensively improves the color, aroma and taste quality of black tea. It not only has good social and economic benefits, but is also easy to operate, suitable for large-scale production, and has low processing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a comparison chart of the relative contents of main aroma substances in the product of the present invention and the product of traditional process; different lowercase letters represent the results of multiple comparisons of each group, the same letters represent no significant difference, and different letters represent significant difference (P<0.05). DETAILED DESCRIPTION

[0054] The present invention is not limited to the following specific embodiments. A person skilled in the art can adopt other various specific embodiments to implement the present invention according to the contents disclosed in the present invention, or any simple changes or modifications made to the design structure and ideas of the present invention fall within the protection scope of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict. The vibration trough used in the experiment is the ZDC-40 vibration trough of Zhejiang Zhufeng Machinery Co., Ltd.

[0055] Example 1

[0056] The fresh leaves of Castanopsis chinensis with one bud and two leaves in summer were placed in a LCWD-5 withering tank, withered for 40 minutes at a relative humidity of 60% and a room temperature of 26°C, and then naturally withered for 8.5 hours at room temperature until the leaf color changed from bright green to dark green, the leaf quality was soft and slightly fragrant; the withered leaves were thinly spread in a ZDC-40 vibration tank, the vibration intensity was set to 0.55 kW, the vibration time was 70 seconds, the tea leaves passed through the vibration tank at a speed of 0.085 m / s, and after completion, they were left to stand for 5 minutes, the second and third vibration conditions were the same, and the tea leaves were left to stand at room temperature. The leaves were allowed to stand for 10 and 15 minutes respectively and then spread to cool; after rolling at 20-22°C using a 6CR-Z55 rolling machine at 48 r / min for 50 minutes, the tea stripping rate was over 70% and the cell damage rate was over 85%; after air rolling for 3 minutes, the leaves were deblocked using a 6CJW-50 deblocking machine; the deblocked leaves were piled in a 4 cm thickness in an intelligent fermentation room and fermented for 1.5 hours at a fermentation temperature of 25-26°C and a relative humidity of 90-95%, until the grass smell of the fermented leaves disappeared and a fresh and rich floral and fruity aroma appeared. The fermented leaves are dried in a 4-72A centrifugal fan at an air inlet temperature of 120°C for 10 seconds; the initially dried leaves are piled in an intelligent fermentation room for fermentation, with a pile thickness of 5 cm, a temperature of 27°C-30°C, and a humidity of 65%-70%; the fermented leaves are baked in a 6CHZ-9B tea roasting machine at 88-89°C until the tea leaves can be twisted into powder by hand and have a moisture content of about 6%, taken out, spread to cool to room temperature, and then sealed for storage.

[0057] After sensory evaluation, the obtained black tea had tight strands, black and smooth color, bright orange-red soup color, rich floral and fruity aroma, mellow taste, and bright red leaf bottom. After the color measurement of tea soup, the lightness (L* value) and red-greenness (a* value) of the black tea soup (100℃) were significantly improved (P<0.05); after the analysis of flavor quality components, the contents of water extract, tea polyphenols, amino acids, caffeine, and soluble sugar in the obtained black tea soup were significantly increased by 14.17%, 43.19%, 7.84%, 30.18%, and 32.76%, respectively (P<0.05); after HPLC detection and analysis, the ratio of ester-type catechins to total catechins in the obtained black tea was significantly reduced ( P<0.05), the contents of theaflavins and polyester catechins increased significantly by 83.33% and 67.56%, respectively (P<0.05); GC-MS analysis showed that a total of 228 aroma substances were detected in the finished tea samples, including alcohols (17), aromatic hydrocarbons (24), phenols (16), aldehydes (26), acids (8), terpenes (23), ketones (18), alkanes (35), alkenes (5), heterocyclic compounds (14) and esters (42). The aroma quality components of the obtained black tea are geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenylethanol, benzaldehyde, trans-β-ionone, nonanal and cis-3-hexenyl-α-methylbutyrate with floral and fruity aroma in contents of 13.12%, 12.69%, 12.61%, 6.29%, 3.25%, 2.23%, 3.09%, 1.51% and 1.16%, respectively. In addition, new floral and fruity aroma components such as 2,4-di-tert-butylphenol, linalool epoxy (furan type), decanal and nonanol were produced.

[0058] Example 2

[0059] Choose fresh leaves of Castanopsis chinensis with one bud and two leaves in autumn as raw materials.

[0060] The fresh leaves of Quercus chinensis with one bud and two leaves in autumn were placed in a LCWD-5 withering tank, with a relative humidity of 60% and a room temperature of 27°C for 40 minutes, and then naturally withered at room temperature for 8 hours, until the leaf color changed from bright green to dark green, the leaf quality was soft and slightly fragrant; the withered leaves were thinly spread in a ZDC-40 vibration tank, the vibration intensity was set to 0.50 kW, the vibration time was 75 seconds, the tea leaves passed through the vibration tank at a speed of 0.085 m / s, and after completion, they were left to stand for 5 minutes, the second and third vibration conditions were the same, and the tea leaves were separated at room temperature. Leave it to stand for 10 and 15 minutes and then spread it to cool; use 6CR-Z55 rolling machine at 48r / min to roll it for 50min at 20-22℃, the tea strip rate is over 70%, the cell damage rate is over 85%, and after 3min of air rolling, use 6CJW-50 deblocking machine to deblock; stack the deblocked leaves with a thickness of 4cm in the intelligent fermentation room and ferment for 1.5h at a fermentation temperature of 25-26℃ and a relative humidity of 90-95%, until the grass smell of the fermented leaves disappears and a fresh and rich floral and fruity aroma appears. The fermented leaves are dried in a 4-72A centrifugal fan at an air inlet temperature of 120°C for 10 seconds; the initially dried leaves are piled in an intelligent fermentation room for fermentation, with a pile thickness of 5 cm, a temperature of 26°C-30°C, and a humidity of 65%-70%; the fermented leaves are baked in a 6CHZ-9B tea roasting machine at 89-90°C until the tea leaves can be twisted into powder by hand and have a moisture content of about 6%, taken out, spread to cool to room temperature, and then sealed for storage.

[0061] After sensory evaluation, the obtained black tea had tight strands, black and smooth color, bright orange-red soup color, rich floral and fruity aroma, mellow taste, and bright red leaf bottom. After the color measurement of tea soup, the lightness (L* value) and red-greenness (a* value) of the black tea soup (100℃) were significantly improved (P<0.05); after the analysis of flavor quality components, the contents of water extract, tea polyphenols, amino acids, caffeine, and soluble sugar in the obtained black tea soup were significantly increased by 20.63%, 13.16%, 7.56%, 31.64%, and 32.76%, respectively (P<0.05); after HPLC detection and analysis, the ratio of ester-type catechins to total catechins in the obtained black tea was significantly reduced ( P<0.05), the contents of theaflavins and polyester catechins increased significantly by 83.33% and 51.35%, respectively (P<0.05); GC-MS analysis showed that a total of 225 aroma substances were detected in the finished tea samples, including alcohols (17), aromatic hydrocarbons (24), phenols (16), aldehydes (26), acids (7), terpenes (22), ketones (18), alkanes (34), alkenes (5), heterocyclic compounds (14) and esters (42). The aroma quality components of the obtained black tea are geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenylethanol, benzaldehyde, trans-β-ionone, nonanal and cis-3-hexenyl-α-methylbutyrate with floral and fruity aroma, with contents of 13.07%, 13.10%, 12.34%, 6.35%, 3.26%, 2.61%, 2.43%, 1.53% and 1.06%, respectively. In addition, new floral and fruity aroma components such as 2,4-di-tert-butylphenol, linalool epoxy (furan type), decanal and nonanol were produced.

[0062] Example 3

[0063] Choose fresh leaves of Castanopsis chinensis with one bud and two leaves in summer as raw materials.

[0064] Place the fresh leaves of Castanopsis chinensis with one bud and two leaves in summer in a LCWD-5 withering tank, wither for 50 minutes at a relative humidity of 60% and a room temperature of 26°C, and then wither naturally at room temperature for 8 hours. The thickness of the withered leaves is 1-1.5 cm, until the leaf color changes from bright green to dark green, the leaves are soft and slightly fragrant; spread the withered leaves thinly in a ZDC-40 vibration tank. The vibration intensity is set to 0.60 kW, the vibration time is 65 seconds, the tea leaves pass through the vibration trough at a speed of 0.085 m / s, and are left to stand for 5 minutes after completion. The second and third vibration conditions are the same, and the tea leaves are left to stand for 10 minutes and 15 minutes at room temperature respectively, and then spread out to cool; after rolling for 50 minutes at 20-22°C using a 6CR-Z55 rolling machine at 48 r / min, the tea leaves have a stripping rate of more than 70%, and a cell breakage rate of more than 85%. After 3 minutes of air rolling, a 6CJW-50 deblocking machine is used to deblock the leaves; the deblocked leaves are piled in an intelligent fermentation room with a thickness of 4 cm and fermented for 1.5 hours at a fermentation temperature of 25-26°C and a relative humidity of 90-95%, until the grass smell of the fermented leaves disappears and a fresh and rich floral and fruity aroma appears. The fermented leaves are dried in a 4-72A centrifugal fan at an air inlet temperature of 120°C for 10 seconds; the initially dried leaves are piled in an intelligent fermentation room for fermentation, with a pile thickness of 5 cm, a temperature of 26°C-30°C, and a humidity of 65%-70%; the fermented leaves are baked in a 6CHZ-9B tea roasting machine at 88-89°C until the tea leaves can be twisted into powder by hand and have a moisture content of about 6%, taken out, spread to cool to room temperature, and then sealed for storage.

[0065] After sensory evaluation, the obtained black tea had tight strands, black and smooth color, bright orange-red soup color, rich floral and fruity aroma, mellow taste, and bright red leaf bottom. After the color measurement of tea soup, the lightness (L* value) and red-greenness (a* value) of the black tea soup (100℃) were significantly improved (P<0.05); after the analysis of flavor quality components, the contents of water extract, tea polyphenols, amino acids, caffeine, and soluble sugar in the obtained black tea soup were significantly increased by 29.24%, 11.93%, 7.28%, 33.82%, and 22.87%, respectively (P<0.05); after HPLC detection and analysis, the ratio of ester-type catechins to total catechins in the obtained black tea was significantly reduced ( P<0.05), the contents of theaflavins and polyester catechins increased significantly by 61.11% and 59.46%, respectively (P<0.05); GC-MS analysis showed that a total of 226 aroma substances were detected in the finished tea samples, including alcohols (17), aromatic hydrocarbons (24), phenols (16), aldehydes (26), acids (7), terpenes (23), ketones (18), alkanes (34), alkenes (5), heterocyclic compounds (14) and esters (42). The aroma quality components of the obtained black tea are geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenylethanol, benzaldehyde, trans-β-ionone, nonanal and cis-3-hexenyl-α-methylbutyrate with floral and fruity aroma, with contents of 12.66%, 11.68%, 12.71%, 6.42%, 3.31%, 2.67%, 2.69%, 1.68% and 1.18%, respectively. In addition, new floral and fruity aroma components such as 2,4-di-tert-butylphenol, linalool epoxy (furan type), decanal and nonanol were produced.

[0066] Comparative Example 1

[0067] Traditional crafts

[0068] The fresh leaves of Quercus chinensis with one bud and two leaves in summer are placed on a LCWD-5 withering trough, and withered for 8 hours under the conditions of relative humidity of 60%, room temperature of 26°C and good ventilation, and the thickness of the withered leaves is 1-1.5 cm, until the leaf color changes from bright green to dark green, the leaves are soft and slightly fragrant; the withered leaves are rolled for 50 minutes at 20-22°C using a 6CR-Z55 rolling machine at 48 r / min to make the tea leaves into strips, and after air rolling for 3 minutes, a 6C JW-50 deblocking machine is used to deblock; the deblocked leaves are piled in an intelligent fermentation room with a thickness of 4 cm and fermented for 1.5 hours, the fermentation temperature is 25-26°C, and the relative humidity is 90-95%. The fermented leaves are dried in a 6CCP-60 bottle-type roasting and drying machine with an air inlet temperature of 100°C for 20 minutes, then taken out and cooled to room temperature, and the cooled leaves are dried in a 6CHZ-9B tea roasting machine at 88-89°C until the tea leaves can be hand-twisted into powder with a moisture content of about 6%; immediately cooled after drying, sealed and stored after cooling, taken out and cooled to room temperature, and sealed and stored after cooling.

[0069] After sensory evaluation, the obtained black tea strands are relatively tight, the color is dark and moist, the soup color is bright red, the aroma is pure, the taste is mellow and slightly green, the leaf bottom is uniform, less red and more green. After the color measurement of the tea soup, the L*, a*, and b* values ​​of the black tea soup (100℃) are 83.64, 0.84, and 55.28 respectively; after the analysis of the flavor quality components, the contents of water extract, tea polyphenols, amino acids, caffeine, and soluble sugar in the obtained black tea soup are 33.35%, 10.14%, 3.57%, 2.75%, and 2.93% respectively; after HPLC detection and analysis, the theaflavins and polyphenols of the obtained black tea are 1.3%, 1.7%, 2.8%, 3.9%, 4.8%, 5.9%, 6.7%, 7.9%, 8.8%, 9.8%, 10.14%, 11.3%, 12.7%, 13.9%, 14.8%, 15.9%, 16.9%, 17.9%, 18.9%, 19.9%, 20.9%, 21.9%, 22.9%. The contents of ester catechins were 0.18% and 0.37% respectively; after GC-MS detection, a total of 191 aroma substances were detected in the finished tea samples, including alcohols (14 kinds), aromatic hydrocarbons (19 kinds), phenols (14 kinds), aldehydes (24 kinds), acids (3 kinds), terpenes (22 kinds), ketones (14 kinds), alkanes (28 kinds), alkenes (5 kinds), heterocyclic compounds (12 kinds) and esters (36 kinds).

[0070] The performance of the finished products prepared in the embodiment and the comparative example is compared, and the data are shown below. Figure 1 In the present invention, this product is a black tea product produced according to the method of the present invention, this product 1, this product 2 and this product 3 respectively correspond to the black tea products processed by Example 1, Example 2 and Example 3 in the specific implementation manner below, and the traditional product corresponds to the black tea product processed by the traditional process embodiment in the specific implementation manner below.

[0071] The sensory quality comparison of black tea (traditional product) processed by traditional technology is shown in Table 1. As can be seen from Table 1, the product of the present invention is significantly superior to the traditional black tea product in terms of sensory color, aroma and taste quality.

[0072] Table 1 Sensory evaluation comparison table

[0073]

[0074] The color difference of the finished black tea processed by the method of the present invention (this product) and the black tea processed by the traditional process (traditional product) is shown in Table 2. As shown in Table 2, the L* value of the tea soup of the three products of the method of the present invention was significantly increased by 6.27%, 6.75%, and 4.59% (P<0.05), and the a* value was increased from 0.84 to 3.35, 3.27, and 3.98, with significant differences (P<0.05), indicating that the brightness and redness of the tea soup were significantly enhanced (P<0.05), which was consistent with the sensory evaluation showing that it had a bright orange-red color, indicating that the method can effectively improve the color quality of black tea soup.

[0075] Table 2 Comparison of tea soup color difference

[0076] deal with L* a* b* Traditional products 83.64±0.22 0.84±0.02 55.28±0.23 This product 1 <![CDATA[88.89±0.20 * ]]> <![CDATA[3.35±0.01 * ]]> 53.33±0.38 This product 2 <![CDATA[89.29±0.30 * ]]> <![CDATA[3.27±0.02 * ]]> 55.17±0.20 This product 3 <![CDATA[87.48±0.11 * ]]> <![CDATA[3.98±0.03 * ]]> 53.29±0.23

[0077] Note: L* value represents brightness, a higher L* value means that the tea soup is brighter and has stronger light transmittance; a* value represents redness and greenness, the higher the a* value, the redder the tea soup color; b* value represents yellow-blue value, the higher the b* value, the yellower the tea soup color. * indicates significant difference compared with traditional products (P<0.05), the same below.

[0078] The water extracts of the three finished black teas (this product) processed by the method of the present invention and the black tea (traditional product) processed by the traditional process were significantly increased by 14.17%, 20.63%, and 29.24% (P<0.05), respectively; the content of tea polyphenols was significantly increased by 14.03%, 13.16%, and 11.93% (P<0.05), respectively; the content of amino acids was significantly increased by 7.84%, 7.56%, and 7.28% (P<0.05), respectively; the content of caffeine was significantly increased by 30.18%, 31.64%, and 33.82% (P<0.05), respectively; and the soluble sugar was also significantly increased by 32.76%, 32.76%, and 22.87% (P<0.05). The above results show that the method can significantly improve the taste quality of black tea.

[0079] Table 3 Contents of water extract, tea polyphenols, amino acids, caffeine and soluble sugar

[0080] Grouping Water extract(%) Tea polyphenols (%) Amino Acid(%) Caffeine(%) Soluble sugar (%) Traditional products 33.35±0.40 16.25±0.06 3.57±0.04 2.75±0.08 2.93±0.06 This product 1 <![CDATA[38.08±0.08 * ]]> <![CDATA[18.53±0.04 * ]]> <![CDATA[3.85±0.02 * ]]> <![CDATA[3.58±0.03 * ]]> <![CDATA[3.89±0.07 * ]]> This product 2 <![CDATA[40.23±0.69 * ]]> <![CDATA[18.39±0.30 * ]]> <![CDATA[3.84±0.03 * ]]> <![CDATA[3.62±0.04 * ]]> <![CDATA[3.89±0.13 * ]]> This product 3 <![CDATA[43.10±0.66 * ]]> <![CDATA[18.19±0.09 * ]]> <![CDATA[3.83±0.03 * ]]> <![CDATA[3.68±0.10 * ]]> <![CDATA[3.60±0.07 * ]]>

[0081] The comparison of catechin content between the finished black tea processed by the method of the present invention (this product) and the black tea processed by the traditional process (traditional product) is shown in Table 4. As shown in Table 4, compared with the traditional product, the ratio of ester catechins to total catechins in the tea samples of the three products of the method of the present invention were significantly reduced (P<0.05).

[0082] Table 4 Comparison of catechin content

[0083]

[0084] Note: Ester catechins: EGCG, GCG, ECG; simple catechins: EGC, C, EC.

[0085] The comparison of theaflavin and polyester catechin content in the finished black tea (this product) processed by the method of the present invention and the black tea (traditional product) processed by the traditional process is shown in Table 5. As shown in Table 4, the theaflavin content in the three product tea samples of the method of the present invention increased significantly by 83.33%, 83.33%, and 61.11% (P<0.05), and the total amount of polyester catechin increased significantly by 67.56%, 51.35%, and 59.46% (P<0.05).

[0086] Table 5 Comparison of the content of theaflavins and polyester catechins

[0087]

[0088] Note: TFs means the total amount of theaflavins, which is the sum of TF1, TF2A, TF2B and TFDG; TSs means the total amount of polyester catechins, which is the sum of TSA, TSB and TSC.

[0089] Comparison of the relative contents of the main aroma substances in the finished black tea processed by the method of the present invention and the black tea processed by the traditional process is as follows Figure 1 As shown. Figure 1 It can be seen that the contents of ketones, esters, heterocyclic substances and phenolic substances in the black tea produced by the method of the present invention are significantly higher than those in the traditional process products (P<0.05).

[0090] Table 6 Comparison of the contents of main floral and fruity aroma compounds

[0091]

[0092]

[0093] Table 6 shows the comparison of the contents of main floral and fruity aroma compounds in the finished black tea processed by the method of the present invention and the black tea processed by the traditional process. As shown in Table 6, the contents of geraniol in the three tea samples processed by the method of the present invention were significantly increased by 55.82%, 55.23%, and 50.36% (P<0.05), respectively; the contents of methyl salicylate were significantly increased by 24.41%, 28.43%, and 14.51% (P<0.05), respectively; the contents of phenylacetaldehyde were significantly increased by 13.30%, 10.88%, and 14.19% (P<0.05), respectively; the contents of linalool were significantly increased by 16.70%, 17.81%, and 19.11% (P<0.05), respectively. 0.05); the contents of phenylacetaldehyde increased significantly by 12.85%, 13.19% and 14.93% respectively (P<0.05); the contents of benzaldehyde increased significantly by 12.06%, 31.16% and 34.17% respectively (P<0.05); the contents of trans-β-ionone increased significantly by 47.14%, 15.71% and 28.10% respectively (P<0.05); the contents of nonanal increased significantly by 8.63%, 10.07% and 20.86% respectively (P<0.05); the contents of cis-3-hexenyl-α-methylbutyrate increased significantly by 36.47%, 24.71% and 38.82% respectively (P<0.05). In addition, the finished black tea processed by the method of the present invention also contains new floral and fruity aroma components such as 2,4-di-tert-butylphenol, epoxy linalool (furan type), decanal and nonanol. The above results show that the method of the present invention can effectively improve the aroma quality of black tea and process floral and fruity black tea products.

[0094] Comparative Example 2

[0095] Only launder vibration without fermentation (compared to Example 3)

[0096] Choose fresh leaves of Castanopsis chinensis with one bud and two leaves in summer as raw materials.

[0097] Place the fresh leaves of Castanopsis chinensis with one bud and two leaves in summer in a LCWD-5 withering tank, wither for 50 minutes at a relative humidity of 60% and a room temperature of 26°C, and then wither naturally at room temperature for 8 hours. The thickness of the withered leaves is 1-1.5 cm, until the leaf color changes from bright green to dark green, the leaves are soft and slightly fragrant; spread the withered leaves thinly in a ZDC-40 vibration tank. The vibration intensity is set to 0.60 kW, the vibration time is 65 seconds, the tea leaves pass through the vibration trough at a speed of 0.085 m / s, and are left to stand for 5 minutes after completion. The second and third vibration conditions are the same, and the tea leaves are left to stand for 10 minutes and 15 minutes at room temperature respectively, and then spread out to cool; after rolling for 50 minutes at 20-22°C using a 6CR-Z55 rolling machine at 48 r / min, the tea leaves have a stripping rate of more than 70%, and a cell breakage rate of more than 85%. After 3 minutes of air rolling, a 6CJW-50 deblocking machine is used to deblock the leaves; the deblocked leaves are piled in an intelligent fermentation room with a thickness of 4 cm and fermented for 1.5 hours at a fermentation temperature of 25-26°C and a relative humidity of 90-95%, until the grass smell of the fermented leaves disappears and a fresh and rich floral and fruity aroma appears. The fermented leaves are dried in a 4-72A centrifugal fan at an air inlet temperature of 120°C for 10 seconds; then taken out and cooled to room temperature, and the cooled leaves are dried in a 6CHZ-9B tea roasting machine at 88-89°C until the tea leaves can be hand-rolled into powder with a moisture content of about 6%; immediately cooled after drying, sealed and stored after cooling, taken out and cooled to room temperature, and sealed and stored after cooling.

[0098] After sensory evaluation, the obtained black tea has tighter strips, dark and moist color, orange-red soup color, pure floral aroma, mellow and slightly green flavor, and uniform, red and green leaves. Compared with the product of the present invention, the product is inferior in strip tightness, moist color of dry tea, rich flower and fruit aroma, mellow taste and uniformity of leaves. After the color measurement of tea soup, the L*, a* and b* values ​​of black tea soup (100°C) are 85.33, 0.91 and 55.08 respectively, and the brightness and red-greenness of the tea soup color are not as good as the finished black tea processed by the method of Examples 1-3. After flavor quality component analysis, the contents of water extract, tea polyphenols, amino acids, caffeine and soluble sugar in the obtained black tea soup were 35.83%, 14.14%, 3.77%, 3.02% and 3.22%, respectively; after HPLC detection and analysis, the contents of theaflavins and polyester catechins in the obtained black tea were 0.20% and 0.38%, respectively; compared with the finished black tea processed in Examples 1-3, the contents of flavor substances such as water extract, tea polyphenols, amino acids, caffeine, soluble sugar, theaflavins and polyester catechins were significantly reduced (P<0.05), resulting in poor taste. Through GC-MS detection, a total of 196 aroma substances were detected in the finished tea samples, including alcohols (15), aromatic hydrocarbons (20), phenols (15), aldehydes (24), acids (3), terpenes (22), ketones (14), alkanes (28), alkenes (7), heterocyclic compounds (12) and esters (36). The contents of geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenylethanol, benzaldehyde and trans-β-ionone with floral and fruity aroma were 10.10%, 10.01%, 7.12%, 3.98%, 3.01%, 2.21% and 2.48% respectively. Compared with the finished black tea processed by the method of Examples 1-3, the black tea is slightly insufficient in the types of aroma substances, the content of various flower and fruit aroma components is significantly reduced (P<0.05), and the overall aroma is not as good as the finished black tea processed by the method of Examples 1-3.

[0099] Comparative Example 3

[0100] No launder vibration, only fermentation (compared to Example 3)

[0101] Choose fresh leaves of Castanopsis chinensis with one bud and two leaves in summer as raw materials.

[0102] Place the fresh leaves of Quercus chinensis with one bud and two leaves in summer in a LCWD-5 withering trough, wither for 50 minutes at a relative humidity of 60% and a room temperature of 26°C, and then naturally wither for 8 hours at room temperature, with a thickness of 1-1.5 cm, until the leaf color changes from bright green to dark green, the leaf texture is soft and slightly fragrant; after rolling for 50 minutes using a 6CR-Z55 rolling machine at 48 r / min at 20-22°C, the tea strip rate is more than 70%, and the cell damage rate is more than 85%. After air rolling for 3 minutes, use a 6CJW-50 deblocking machine to deblock; the deblocked leaves are piled in an intelligent fermentation room with a thickness of 4 cm and fermented for 1.5 hours at a fermentation temperature of 25-26°C and a relative humidity of 90-95%, until the grass smell of the fermented leaves disappears and a fresh and strong floral and fruity aroma appears. The fermented leaves are dried in a 4-72A centrifugal fan at an air inlet temperature of 120°C for 10 seconds; the initially dried leaves are piled in an intelligent fermentation room for fermentation, with a pile thickness of 4 cm, a temperature of 26°C-30°C, and a humidity of 65%-70%; the fermented leaves are baked in a 6CHZ-9B tea roasting machine at 88-89°C until the tea leaves can be twisted into powder by hand and have a moisture content of about 6%, taken out, spread to cool to room temperature, and then sealed for storage.

[0103] After sensory evaluation, the obtained black tea strips were relatively tight, the color was dark and moist, the soup color was slightly dark red, the aroma was low and dull, the taste was bland, and the leaf bottom was red and slightly dark. Compared with the products of Examples 1-3, the product was not good in terms of strip tightness, dry tea color, richness of flower and fruit aroma, mellowness of taste, and brightness of leaf bottom. After the color measurement of tea soup, the L*, a*, and b* values ​​of the black tea soup (100°C) were 80.33, 2.11, and 56.38, respectively. The brightness and red-greenness of the tea soup color were not as good as those of the finished black tea processed by the method of Examples 1-3. The contents of tea extract, tea polyphenols, amino acids, caffeine and soluble sugar in the obtained black tea soup were 38.12%, 16.14%, 3.42%, 2.80% and 3.41%, respectively. The contents of theaflavins and polyester catechins in the obtained black tea were 0.31% and 0.52%, respectively, and the contents of various flavor substances were significantly lower than those of the finished black tea processed by the method of Examples 1-3 (P<0.05). The GC-MS test showed that a total of 190 aroma substances were detected in the finished tea samples, including 14 alcohols. , aromatic hydrocarbons (19 kinds), phenols (14 kinds), aldehydes (24 kinds), acids (3 kinds), terpenes (22 kinds), ketones (14 kinds), alkanes (27 kinds), olefins (5 kinds), heterocyclic compounds (12 kinds) and esters (36 kinds), the contents of geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenylethanol, benzaldehyde and trans-β-ionone with floral and fruity aroma in the obtained black tea aroma quality components are 9.29%, 8.03%, 5.02%, 3.37%, 3.43%, 1.91% and 2.44% respectively. Compared with the finished black tea processed by the method of Examples 1-3, the black tea is slightly insufficient in the types of aroma substances, the contents of various floral and fruity aroma components are significantly reduced (P<0.05), and the overall aroma is not as good as the finished black tea processed by the method of Examples 1-3.

[0104] Comparative Example 4

[0105] The flow channel vibration frequency is lower (compared to Example 3)

[0106] Choose fresh leaves of Castanopsis chinensis with one bud and two leaves in summer as raw materials.

[0107] Place the fresh leaves of Castanopsis chinensis with one bud and two leaves in summer in a LCWD-5 withering tank, with a relative humidity of 60% and a room temperature of 26°C for 50 minutes, and then naturally wither at room temperature for 8 hours. The thickness of the withered leaves is 1-1.5 cm, until the leaf color changes from bright green to dark green, the leaves are soft and slightly fragrant; spread the withered leaves thinly in a ZDC-40 vibration tank. Set the vibration intensity to 0.30 kW and the vibration time to 65 seconds. The tea leaves pass through the vibration tank at a speed of 0.085 m / s, and then stand for 5 minutes. The second and third vibration conditions are the same. The tea leaves are left to stand at room temperature for 10 minutes and 15 minutes respectively, then spread out to cool. After rolling for 50 minutes at 20-22°C using a 6CR-Z55 rolling machine at 48 r / min, the tea stripping rate is over 70%, and the cell damage rate is over 85%. After air rolling for 3 minutes, a 6CJW-50 deblocking machine is used to deblock the leaves. The deblocked leaves are piled in an intelligent fermentation room with a thickness of 4 cm and fermented for 1.5 hours at a fermentation temperature of 25-26°C and a relative humidity of 90-95%, until the grass smell of the fermented leaves disappears and a fresh and rich floral and fruity aroma appears. The fermented leaves are dried in a 4-72A centrifugal fan at an air inlet temperature of 120°C for 10 seconds; the initially dried leaves are piled in an intelligent fermentation room for fermentation, with a pile thickness of 4 cm, a temperature of 26°C-30°C, and a humidity of 65%-70%; the fermented leaves are baked in a 6CHZ-9B tea roasting machine at 88-89°C until the tea leaves can be twisted into powder by hand and have a moisture content of about 6%, taken out, spread to cool to room temperature, and then sealed for storage.

[0108] After sensory evaluation, the obtained black tea has tighter strips, darker and smoother color, brighter red soup color, pure aroma with floral and fruity fragrance, mellow taste, and red and uniform leaf bottom. Compared with the products of Examples 1-3, the product is not as good in terms of strip tightness, smoothness of dry tea color, and richness of floral and fruity aroma. After the color measurement of tea soup, the L*, a*, and b* values ​​of the black tea soup (100°C) are 85.12, 2.21, and 55.43, respectively. The brightness and red-greenness of the tea soup color are not as good as those of the finished black tea processed by the method of Examples 1-3. After analyzing the flavor quality components, the contents of tea extract, tea polyphenols, amino acids, caffeine, and soluble sugar in the obtained black tea soup were 35.83%, 17.92%, 3.70%, 3.21%, and 3.50%, respectively; after HPLC analysis, the contents of theaflavins and polyester catechins in the obtained black tea were 0.30% and 0.52%, respectively, and the contents of each flavor substance were significantly lower than those of the finished black tea processed by the methods of Examples 1-3 (P<0.05). After GC-MS detection, a total of 222 aroma substances were detected in the finished tea samples, including alcohols (17 species), aromatic hydrocarbons (22 species), phenols (16 species), aldehydes (26 species), acids (8 species), terpenes (23 species), ketones (18 species), alkanes (31 species), olefins (5 species), heterocyclic compounds (14 species), and esters (42 species). The contents of geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenylethanol, benzaldehyde, trans-β-ionone, nonanal and cis-3-hexenyl-α-methylbutyrate with floral and fruity aroma in the aroma quality components of the obtained black tea are 9.45%, 10.16%, 9.21%, 4.86%, 3.01%, 1.70%, 2.61%, 0.99% and 0.51%, respectively. Compared with the finished black tea processed by the method of Examples 1-3, the black tea is slightly insufficient in the types of aroma substances, the contents of various floral and fruity aroma components are significantly reduced (P<0.05), and the overall aroma is not as good as the finished black tea processed by the method of Examples 1-3.

[0109] Comparative Example 5

[0110] The flow trough vibrates only for one round - short time (compared to Example 3)

[0111] Choose fresh leaves of Castanopsis chinensis with one bud and two leaves in summer as raw materials.

[0112] Place the fresh leaves of Castanopsis chinensis with one bud and two leaves in summer in a LCWD-5 withering tank, with a relative humidity of 60% and a room temperature of 26℃ for 50 minutes, and then naturally wither at room temperature for 8 hours. The thickness of the withered leaves is 1-1.5cm, until the leaf color changes from bright green to dark green, the leaves are soft and slightly fragrant; spread the withered leaves thinly in a ZDC-40 vibration tank. Set the vibration intensity to 0.60kW and the vibration time to 65 seconds. The tea leaves pass through the vibration tank at a speed of 0.085 m / s, and then stand for 5 minutes. After rolling for 50 minutes at 20-22°C using a 6CR-Z55 rolling machine at 48r / min, the tea stripping rate is over 70%, and the cell damage rate is over 85%. After air rolling for 3 minutes, the tea is deblocked using a 6CJW-50 deblocking machine; the deblocked leaves are piled in a 4cm thickness in an intelligent fermentation room and fermented for 1.5h at a fermentation temperature of 25-26°C and a relative humidity of 90-95%, until the grass smell of the fermented leaves disappears and a fresh and rich floral and fruity aroma appears. The fermented leaves are dried in a 4-72A centrifugal fan at an air inlet temperature of 120°C for 10 seconds; the initially dried leaves are piled in an intelligent fermentation room for fermentation, with a pile thickness of 4 cm, a temperature of 26°C-30°C, and a humidity of 65%-70%; the fermented leaves are baked in a 6CHZ-9B tea roasting machine at 88-89°C until the tea leaves can be twisted into powder by hand and have a moisture content of about 6%, taken out, spread to cool to room temperature, and then sealed for storage.

[0113] After sensory evaluation, the obtained black tea has tighter strips, darker and smoother color, brighter red soup color, pure aroma with floral and fruity fragrance, mellow taste, and red and uniform leaf bottom. Compared with the products of Examples 1-3, the product is not as good in terms of strip tightness, smoothness of dry tea color, and richness of floral and fruity fragrance. After the color measurement of tea soup, the L*, a*, and b* values ​​of the black tea soup (100°C) are 80.02, 2.01, and 55.33, respectively. The brightness and red-greenness of the tea soup color are not as good as those of the finished black tea processed by the method of Examples 1-3. After analyzing the flavor quality components, the contents of tea extract, tea polyphenols, amino acids, caffeine, and soluble sugar in the obtained black tea soup were 38.51%, 16.64%, 3.27%, 2.34%, and 3.28%, respectively; after HPLC analysis, the contents of theaflavins and polyester catechins in the obtained black tea were 0.32% and 0.49%, respectively, and the contents of each flavor substance were significantly lower than those of the finished black tea processed by the methods of Examples 1-3 (P<0.05). After GC-MS detection, a total of 192 aroma substances were detected in the finished tea samples, including alcohols (14 species), aromatic hydrocarbons (20 species), phenols (14 species), aldehydes (24 species), acids (3 species), terpenes (22 species), ketones (14 species), alkanes (28 species), olefins (5 species), heterocyclic compounds (12 species), and esters (36 species). The contents of geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenylethanol, benzaldehyde and trans-β-ionone with floral and fruity aroma in the aroma quality components of the obtained black tea are 10.35%, 9.92%, 9.31%, 5.93%, 4.25%, 2.69% and 3.83%, respectively. Compared with the finished black tea processed by the method of Examples 1-3, the black tea is inferior to the product of the present invention in terms of the types of aroma substances, the contents of various floral and fruity aroma components are significantly reduced (P<0.05), and the overall aroma is inferior to the finished black tea processed by the method of Examples 1-3.

[0114] Comparative Example 6

[0115] The launder vibration process sequence is adjusted after fermentation (compared to Example 3)

[0116] Choose fresh leaves of Castanopsis chinensis with one bud and two leaves in summer as raw materials.

[0117] Place the fresh leaves of Quercus chinensis with one bud and two leaves in summer in a LCWD-5 withering tank, wither for 50 minutes at a relative humidity of 60% and a room temperature of 26°C, and then naturally wither for 8 hours at room temperature, with a thickness of 1-1.5 cm, until the leaf color changes from bright green to dark green, the leaves are soft and slightly fragrant; after rolling for 50 minutes using a 6CR-Z55 rolling machine at 48 r / min at 20-22°C, the tea stripping rate is more than 70%, and after 3 minutes of air rolling, use a 6CJW-50 deblocking machine to deblock; stack the deblocked leaves in a 4 cm thickness in an intelligent fermentation room for fermentation for 1.5 hours, the fermentation temperature is 25-26°C, and the relative humidity is 90-95%, until the grass smell of the fermented leaves disappears, and a fresh and strong floral and fruity aroma appears. Spread the above fermented leaves thinly in a ZDC-40 vibration tank. The vibration intensity is set to 0.60kW, the vibration time is 65 seconds, and the tea leaves pass through the vibration tank at a speed of 0.085 m / s. After completion, let it stand for 5 minutes. The second and third vibration conditions are the same. The tea leaves are left to stand for 10 minutes and 15 minutes at room temperature respectively before cooling. The above-mentioned cooled leaves are dried for 10 seconds at an air inlet temperature of 120°C in a 4-72A centrifugal fan; the above-mentioned initially dried leaves are piled in an intelligent fermentation room for fermentation, with a pile thickness of 4cm, a temperature of 26°C-30°C, and a humidity of 65%-70%; the above-mentioned fermented leaves are baked in a 6CHZ-9B tea roasting machine at 88-89°C until the tea leaves can be twisted into powder by hand, and the water content is about 6%. Take them out, let them cool to room temperature, and then seal them for storage.

[0118] After sensory evaluation, the obtained black tea strips were not tight, the color was dark and moist, the soup color was slightly dark red, the aroma was low and dull, the taste was bland, and the leaf bottom was red and slightly dark. Compared with the products of Examples 1-3, the product was not good in terms of strip tightness, dry tea color, richness of flower and fruit aroma, mellowness of taste, and brightness of leaf bottom. After the color measurement of tea soup, the L*, a*, and b* values ​​of the black tea soup (100°C) were 79.81, 2.92, and 56.28, respectively. The brightness and red-greenness of the tea soup color were not as good as those of the finished black tea processed by the method of Examples 1-3. After analyzing the flavor quality components, the contents of tea extract, tea polyphenols, amino acids, caffeine, and soluble sugar in the obtained black tea soup were 37.47%, 16.89%, 3.33%, 2.76%, and 3.50%, respectively. After HPLC analysis, the contents of theaflavins and polyester catechins in the obtained black tea were 0.23% and 0.49%, respectively. The contents of various flavor substances were significantly lower than those of the finished black tea processed by the method of Examples 1-3 (P<0.05). After GC-MS analysis, a total of 191 aroma substances were detected in the finished tea samples, including alcohols (14 kinds), Aromatic hydrocarbons (19 species), phenols (14 species), aldehydes (24 species), acids (3 species), terpenes (22 species), ketones (14 species), alkanes (27 species), alkenes (5 species), heterocyclic compounds (12 species) and esters (37 species), the contents of geraniol, methyl salicylate, phenylacetaldehyde, linalool, phenylethanol, benzaldehyde and trans-β-ionone with floral and fruity aroma in the obtained black tea aroma quality components are 8.29%, 9.23%, 11.01%, 4.72%, 2.99%, 1.04% and 1.98% respectively. Compared with the finished black tea processed by the method of Examples 1-3, the black tea is slightly insufficient in the types of aroma substances, the contents of various floral and fruity aroma components are significantly reduced (P<0.05), and the overall aroma is not as good as the finished black tea processed by the method of Examples 1-3.

[0119] It should be noted that the above embodiments are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the embodiments here. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for processing black tea, characterized in that: The following steps are involved: S1. Withering: placing fresh tea leaves in a withering tank for withering to obtain withered leaves; S2, vibration: placing the withered leaves in a vibration tank to transmit vibration to obtain cooling leaves; S3, rolling and twisting: rolling and twisting the spread-out leaves to de-block them, thereby obtaining de-blocked leaves; S4, fermentation: put the deblocked leaves into a fermentation room at a temperature of 25°C-28°C and a humidity of 90%-95% for fermentation until 85% of the leaves turn red and yellow; S5, primary drying: drying the tea leaves fermented in step S4 at 115-125°C, and then letting them stand to cool; S6, fermentation: placing the tea leaves that have been initially dried in step S5 in a fermentation room for fermentation to obtain fermented leaves; S7. Fully dry: Dry the fermented leaves at 85-95℃ until the moisture content is less than 7%.

2. The processing method according to claim 1, characterized in that: Fresh tea leaves are fresh leaves from summer or autumn.

3. The processing method according to claim 1, characterized in that: The withering temperature in step S1 is 25-27°C and the humidity is 60%-70%; first withering in a ventilated environment for 30-60 minutes, and then naturally withering for 8-9 hours to obtain withered leaves.

4. The processing method according to claim 1, characterized in that: The process of transmission vibration in step S2 is: the vibration power is 0.50-0.60 kW, the transmission speed is 0.080-0.090 m / s, the transmission vibration is 65-75s and then left to stand; and it is repeated several times.

5. The processing method according to claim 4, characterized in that: The transmission vibration process in step S2 is: let it stand for 3-7 minutes after the first transmission vibration, let it stand for 8-12 minutes after the second transmission vibration, and let it stand for 13-18 minutes after the third transmission vibration.

6. The processing method according to claim 1, characterized in that: The kneading process in step S3 is: first kneading for 40-60 minutes at a certain frequency in a kneading machine, and then kneading in the air for 3-5 minutes; the kneading frequency is 40-55 r / min.

7. The processing method according to claim 1, characterized in that: In step S4, the fermented tea leaves are piled up to a thickness of 3.5-4.5 cm, and the fermentation time is 1.5-2 h.

8. The processing method according to claim 1, characterized in that: In step S6, the fermentation temperature is 27-30°C, the humidity is 65%-70%, and the fermentation time is 3.5-4h.

9. The processing method according to claim 1, characterized in that: The fermented tea leaves in step S6 are stacked to a thickness of 5-6 cm.

10. The processing method according to any one of claims 1 to 9, characterized in that: When the tea leaves are fully dried in step S7, the thickness of the tea leaves is 1-2 cm.

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